Immunology mnemonic
Cytokines Mnemonic — Interleukins, Interferons, TNF, TGF
The cytokine table is one of the hardest single pages in First Aid immunology. Ellie turns it into a deck that sticks in 2 weeks.
The First Aid cytokine table has ~15 interleukins plus IFN-α/β/γ, TGF-β, and TNF-α — each with a source cell and a target/function. This is pure memorization with no obvious pattern, which is exactly what spaced repetition solves.
This page gives you the mnemonic hooks that make each interleukin sticky (hot T-BONE stEAK for IL-1 through IL-6, IL-8 → chemokine, IL-10/TGF-β → anti-inflammatory), then the full high-yield table.
The hot T-BONE stEAK mnemonic — IL-1 through IL-6
The classic mnemonic for the first six interleukins uses effects rather than sources:
- Hot — IL-1 → fever (endogenous pyrogen)
- T — IL-2 → stimulates T cells
- BONE — IL-3 → bone marrow stem cell activation
- stE — IL-4 → IgE class-switching (allergy)
- A — IL-5 → IgA class-switching + eosinophils
- K — IL-6 → aKute-phase reactants + fever
The full high-yield cytokine table
Beyond the mnemonic, these are the cytokines Step 1 tests:
- IL-1 — macrophages → fever, acute inflammation, endothelial activation
- IL-2 — Th cells → T-cell proliferation (target of daclizumab, basiliximab)
- IL-3 — T cells → bone marrow stem cells (functions like GM-CSF)
- IL-4 — Th2 → B-cell class-switching to IgE + IgG
- IL-5 — Th2 → B-cell class-switching to IgA + eosinophil activation (target of mepolizumab in asthma)
- IL-6 — macrophages/Th2 → acute-phase reactants (CRP, fibrinogen) + fever (target of tocilizumab in CRS)
- IL-8 — macrophages → neutrophil chemotaxis (Clean up on aisle 8)
- IL-10 — Treg → anti-inflammatory (dampens Th1)
- IL-12 — macrophages → Th1 differentiation + NK activation (deficiency → disseminated mycobacterial infection)
- IL-17 — Th17 → neutrophil recruitment (target of secukinumab in psoriasis)
- IFN-α, IFN-β — antiviral (upregulate MHC-I on infected cells)
- IFN-γ — Th1/NK → macrophage activation (defective signaling → mycobacterial disease)
- TNF-α — macrophages → cachexia, fever, granuloma maintenance (target of infliximab, etanercept; TB reactivation risk)
- TGF-β — Treg → anti-inflammatory + IgA class-switching + fibrosis
Clinical hooks that anchor memory
Each cytokine has a clinical anchor that makes it stick:
- TNF-α → anti-TNF drugs → TB reactivation (screen with PPD before starting infliximab)
- IL-6 → tocilizumab → cytokine release syndrome after CAR-T therapy
- IL-5 → mepolizumab/reslizumab → severe eosinophilic asthma
- IL-17 → secukinumab → psoriasis + ankylosing spondylitis
- IL-12 → deficiency → disseminated Mycobacterium infection in children
- IFN-γ → defective STAT1 signaling → mycobacterial disease
Frequently asked questions
How do I remember IL-4 vs IL-5 IgE vs IgA?
IL-4 → IgE (both have 'E'). IL-5 → IgA + eosinophils. Or: E for allergy (Type I hypersensitivity, IgE), A for mucosal (IgA at mucosal surfaces). IL-4 and IL-5 are both Th2 cytokines.
What's the difference between IL-10 and TGF-β?
Both are anti-inflammatory cytokines from Tregs. IL-10 primarily suppresses Th1 responses. TGF-β additionally promotes IgA class-switching and fibrosis (target in scleroderma and pulmonary fibrosis).
Which cytokines are targeted by biologic drugs on Step 1?
TNF-α (infliximab, adalimumab, etanercept — RA, IBD, psoriasis), IL-6 (tocilizumab — RA, giant cell arteritis, CRS), IL-17 (secukinumab — psoriasis), IL-5 (mepolizumab — asthma), IL-4/IL-13 (dupilumab — atopic dermatitis, asthma), IL-2 receptor (basiliximab — transplant).
Why does anti-TNF therapy reactivate TB?
TNF-α is required to maintain granuloma integrity. Latent TB is contained within granulomas. Blocking TNF-α causes granuloma breakdown → reactivation. All patients get PPD or IGRA screening before starting anti-TNF therapy.
Is Th1/Th2/Th17 differentiation on Step 1?
Yes. Th1 driven by IL-12 → IFN-γ → macrophage activation (intracellular pathogens). Th2 driven by IL-4 → IL-4/5/13 → B-cell isotype switching + eosinophils (parasites, allergy). Th17 driven by TGF-β + IL-6 + IL-23 → IL-17 → neutrophil recruitment (extracellular bacteria, fungi).
How many cards for the cytokine deck?
~80–120 atomic cards. Each cytokine gets source + target + clinical hook cards.
Keep exploring
Authoritative sources
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